Clutches are frequently arranged in present-day motor vehicles between an internal-combustion engine and a transmission, and are therefore known. The disk is in this case frequently constructed as a flywheel disk and fastened on a drive shaft of the internal-combustion engine. When the limit of wear is reached, the friction lining has a minimum thickness and must be exchanged.
A brake known in practice has an electric conductor, through which a signal current flows, in a friction lining in the region of the limit of wear. When the limit of wear of the friction lining is reached, the electric conductor is severed and the signal current is interrupted. The interruption of the signal current thus signals that the minimum thickness of the friction lining has been reached.
This brake has the advantage that it supplies an unambiguous electric switching signal when a minimum thickness of the friction lining has been reached.
By contrast with analog signals, digital signals are largely independent of temperature and can easily be assigned to a specific state. In this case, the electric signals generated are also independent of an adjusting device arranged on the actuating device (pedal and lever device). Furthermore, it is possible for a warning lamp, for example, to be activated on a dashboard of the motor vehicle with little electronic outlay.
However, it is disadvantageous in the known brake that the way in which contact is made with the electric conductor in the rotating friction lining, for example via sliding contacts or induction coils, is very complicated and vulnerable. Furthermore, the electric conductors have manufacturing tolerances, and frequently cannot be arranged reliably in a prescribed position in the friction lining.
Thus, there is a need for a clutch of the type mentioned at the beginning such that it is possible to determine in a particularly accurate fashion with a low outlay and without the risk of erroneous measurements that the minimum thickness of the friction lining has been reached. Other needs will become apparent upon a further reading of the following detailed description taken in conjunction with the drawings.